The group_sched_in() function uses a transactional approach to schedule
a group of events. In a group, either all events can be scheduled or
none are. To schedule each event in, the function calls event_sched_in().
In case of error, event_sched_out() is called on each event in the group.

The problem is that event_sched_out() does not completely cancel the
effects of event_sched_in(). Furthermore event_sched_out() changes the
state of the event as if it had run which is not true is this particular
case.

Those inconsistencies impact time tracking fields and may lead to events
in a group not all reporting the same time_enabled and time_running values.
This is demonstrated with the example below:

$ task -eunhalted_core_cycles,baclears,baclears -e unhalted_core_cycles,baclears,baclears sleep 5
1946101 unhalted_core_cycles (32.85% scaling, ena=829181, run=556827)
  11423 baclears (32.85% scaling, ena=829181, run=556827)
   7671 baclears (0.00% scaling, ena=556827, run=556827)

2250443 unhalted_core_cycles (57.83% scaling, ena=962822, run=405995)
  11705 baclears (57.83% scaling, ena=962822, run=405995)
  11705 baclears (57.83% scaling, ena=962822, run=405995)

Notice that in the first group, the last baclears event does not
report the same timings as its siblings.

This issue comes from the fact that tstamp_stopped is updated
by event_sched_out() as if the event had actually run.

To solve the issue, we must ensure that, in case of error, there is
no change in the event state whatsoever. That means timings must
remain as they were when entering group_sched_in().

To do this we defer updating tstamp_running until we know the
transaction succeeded. Therefore, we have split event_sched_in()
in two parts separating the update to tstamp_running.

Similarly, in case of error, we do not want to update tstamp_stopped.
Therefore, we have split event_sched_out() in two parts separating
the update to tstamp_stopped.

With this patch, we now get the following output:

$ task -eunhalted_core_cycles,baclears,baclears -e unhalted_core_cycles,baclears,baclears sleep 5
2492050 unhalted_core_cycles (71.75% scaling, ena=1093330, run=308841)
  11243 baclears (71.75% scaling, ena=1093330, run=308841)
  11243 baclears (71.75% scaling, ena=1093330, run=308841)

1852746 unhalted_core_cycles (0.00% scaling, ena=784489, run=784489)
   9253 baclears (0.00% scaling, ena=784489, run=784489)
   9253 baclears (0.00% scaling, ena=784489, run=784489)

Note that the uneven timing between groups is a side effect of
the process spending most of its time sleeping, i.e., not enough
event rotations (but that's a separate issue).
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4cb86b4c.41e9d80a.44e9.3e19@mx.google.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

PERF_COUNT_HW_CACHE_DTLB:READ:MISS had a bogus umask value of 0 which
counts nothing. Needed to be 0x7 (to count all possibilities).

PERF_COUNT_HW_CACHE_ITLB:READ:MISS had a bogus umask value of 0 which
counts nothing. Needed to be 0x3 (to count all possibilities).
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: <stable@kernel.org> # as far back as it applies
LKML-Reference: <4cb85478.41e9d80a.44e2.3f00@mx.google.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

You can only call update_context_time() when the context
is active, i.e., the thread it is attached to is still running.

However, perf_event_read() can be called even when the context
is inactive, e.g., user read() the counters. The call to
update_context_time() must be conditioned on the status of
the context, otherwise, bogus time_enabled, time_running may
be returned. Here is an example on AMD64. The task program
is an example from libpfm4. The -p prints deltas every 1s.

$ task -p -e cpu_clk_unhalted sleep 5
    2,266,610 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
	    0 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
	    0 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
	    0 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
	    0 cpu_clk_unhalted (0.00% scaling, ena=2,158,982, run=2,158,982)
5,242,358,071 cpu_clk_unhalted (99.95% scaling, ena=5,000,359,984, run=2,319,270)

Whereas if you don't read deltas, e.g., no call to perf_event_read() until
the process terminates:

$ task -e cpu_clk_unhalted sleep 5
    2,497,783 cpu_clk_unhalted (0.00% scaling, ena=2,376,899, run=2,376,899)

Notice that time_enable, time_running are bogus in the first example
causing bogus scaling.

This patch fixes the problem, by conditionally calling update_context_time()
in perf_event_read().
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org
LKML-Reference: <4cb856dc.51edd80a.5ae0.38fb@mx.google.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Merge branch 'tip/perf/recordmcount' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core

The C version of recordmcount is compiled to a binary, which will
end up located in the objtree. If the kernel is built with O=path,
the srctree will not include the binary recordmcount caller.

Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The file kernel/trace/ftrace.c references the mcount() call to
convert the mcount() callers to nops. But because it references
mcount(), the mcount() address is placed in the relocation table.

The C version of recordmcount reads the relocation table of all
object files, and it will add all references to mcount to the
__mcount_loc table that is used to find the places that call mcount()
and change the call to a nop. When recordmcount finds the mcount reference
in kernel/trace/ftrace.o, it saves that location even though the code
is not a call, but references mcount as data.

On boot up, when all calls are converted to nops, the code has a safety
check to determine what op code it is actually replacing before it
replaces it. If that op code at the address does not match, then
a warning is printed and the function tracer is disabled.

The reference to mcount in ftrace.c, causes this warning to trigger,
since the reference is not a call to mcount(). The ftrace.c file is
not compiled with the -pg flag, so no calls to mcount() should be
expected.

This patch simply makes recordmcount.c skip the kernel/trace/ftrace.c
file. This was the same solution used by the perl version of
recordmcount.
Reported-by: NIngo Molnar <mingo@elte.hu>
Cc: John Reiser <jreiser@bitwagon.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Make !CONFIG_PM function stubs static inline and remove section
attribute.
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Commit e9677b3c (oprofile, ARM: Use oprofile_arch_exit() to
cleanup on failure) caused oprofile_perf_exit to be called
in the cleanup path of oprofile_perf_init. The __exit tag
for oprofile_perf_exit should therefore be dropped.

The same has to be done for exit_driverfs as well, as this
function is called from oprofile_perf_exit. Else, we get
the following two linker errors.

  LD      .tmp_vmlinux1
`oprofile_perf_exit' referenced in section `.init.text' of arch/arm/oprofile/built-in.o: defined in discarded section `.exit.text' of arch/arm/oprofile/built-in.o
make: *** [.tmp_vmlinux1] Error 1

  LD      .tmp_vmlinux1
`exit_driverfs' referenced in section `.text' of arch/arm/oprofile/built-in.o: defined in discarded section `.exit.text' of arch/arm/oprofile/built-in.o
make: *** [.tmp_vmlinux1] Error 1
Signed-off-by: NAnand Gadiyar <gadiyar@ti.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

oprofile_perf.c needs to include platform_device.h
Otherwise we get the following build break.

  CC      arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.o
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:192: warning: 'struct platform_device' declared inside parameter list
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:192: warning: its scope is only this definition or declaration, which is probably not what you want
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:201: warning: 'struct platform_device' declared inside parameter list
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:210: error: variable 'oprofile_driver' has initializer but incomplete type
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:211: error: unknown field 'driver' specified in initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:211: error: extra brace group at end of initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:211: error: (near initialization for 'oprofile_driver')
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:213: warning: excess elements in struct initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:213: warning: (near initialization for 'oprofile_driver')
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:214: error: unknown field 'resume' specified in initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:214: warning: excess elements in struct initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:214: warning: (near initialization for 'oprofile_driver')
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:215: error: unknown field 'suspend' specified in initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:215: warning: excess elements in struct initializer
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c:215: warning: (near initialization for 'oprofile_driver')
arch/arm/oprofile/../../../drivers/oprofile/oprofile_perf.c: In function 'init_driverfs':
Signed-off-by: NAnand Gadiyar <gadiyar@ti.com>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Conflicts:
	arch/arm/oprofile/common.c
	kernel/perf_event.c

Merge branch 'tip/perf/recordmcount-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core

The config option used by archs to let the build system know that
the C version of the recordmcount works for said arch is currently
called HAVE_C_MCOUNT_RECORD which enables BUILD_C_RECORDMCOUNT. To
be more consistent with the name that all archs may use, it has been
renamed to HAVE_C_RECORDMCOUNT. This will be less confusing since
we are building a C recordmcount and not a mcount_record.
Suggested-by: NIngo Molnar <mingo@elte.hu>
Cc: <linux-arch@vger.kernel.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Cc: John Reiser <jreiser@bitwagon.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core

The elf reader for recordmcount.c had duplicate functions for both
32 bit and 64 bit elf handling. This was due to the need of using
the 32 and 64 bit elf structures.

This patch consolidates the two by using macros to define the 32
and 64 bit names in a recordmcount.h file, and then by just defining
a RECORD_MCOUNT_64 macro and including recordmcount.h twice we
create the funtions for both the 32 bit version as well as the
64 bit version using one code source.

Cc: John Reiser <jreiser@bitwagon.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

This patch adds the support for the C version of recordmcount and
compile times show ~ 12% improvement.

After verifying this works, other archs can add:

 HAVE_C_MCOUNT_RECORD

in its Kconfig and it will use the C version of recordmcount
instead of the perl version.

Cc: <linux-arch@vger.kernel.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Cc: John Reiser <jreiser@bitwagon.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Currently, the mcount callers are found with a perl script that does
an objdump on every file in the kernel. This is a C version of that
same code which should increase the performance time of compiling
the kernel with dynamic ftrace enabled.
Signed-off-by: NJohn Reiser <jreiser@bitwagon.com>

[ Updated the code to include .text.unlikely section as well as
  changing the format to follow Linux coding style. ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

In x86, faults exit by executing the iret instruction, which then
reenables NMIs if we faulted in NMI context. Then if a fault
happens in NMI, another NMI can nest after the fault exits.

But we don't yet support nested NMIs because we have only one NMI
stack. To prevent from that, check that vmalloc and kmemcheck
faults don't happen in this context. Most of the other kernel faults
in NMIs can be more easily spotted by finding explicit
copy_from,to_user() calls on review.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>

Since the text_poke_smp() definately depends on actual
stop_machine() on smp, add that dependency to Kconfig.
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
LKML-Reference: <20101014031042.4100.90877.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use __stop_machine() in text_poke_smp() because the caller
must get online_cpus before calling text_poke_smp(), but
stop_machine() do it again. We don't need it.
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
LKML-Reference: <20101014031036.4100.83989.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Define dummy __stop_machine() function even when
CONFIG_STOP_MACHINE=n. This getcpu-required version of
stop_machine() will be used from poke_text_smp().
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20101014031030.4100.34156.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix selftest to clear flags field for reusing probes
because the flags field can be modified by Kprobes.
This also set NULL to kprobe.addr instead of 0.
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101014031024.4100.50107.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Update kprobes.txt about interrupts disabled state inside
kprobes handlers, because optimized probe/boosted kretprobe
run without disabling interrrupts on x86.
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101014031018.4100.64883.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix this linux-next build failure that Stephen reported:

 arch/arm/kernel/perf_event.c: In function 'armpmu_event_init':
 arch/arm/kernel/perf_event.c:543: error: request for member 'num_events' in something not a structure or union
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus <paulus@samba.org>
LKML-Reference: <20101014164925.4fa16b75.sfr@canb.auug.org.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix

kernel/trace/trace_functions_graph.c: In function ‘trace_print_graph_duration’:
kernel/trace/trace_functions_graph.c:652: warning: comparison of distinct pointer types lacks a cast

when building 36-rc6 on a 32-bit due to the strict type check failing
in the min() macro.
Signed-off-by: NBorislav Petkov <bp@alien8.de>
Cc: Chase Douglas <chase.douglas@canonical.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20100929080823.GA13595@liondog.tnic>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Oprofile counters are setup when profiling is disabled. Thus, writing
to oprofilefs has no immediate effect. Changes are updated only after
oprofile is reenabled.

To keep userland and kernel states synchronized, we now allow
configuration of oprofile only if profiling is disabled.  In this case
it checks if the profiler is running and then disables write access to
oprofilefs by returning -EBUSY. The change should be backward
compatible with current oprofile userland daemon.
Acked-by: NMaynard Johnson <maynardj@us.ibm.com>
Cc: William Cohen <wcohen@redhat.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Conflicts:
	arch/arm/oprofile/common.c
Signed-off-by: NRobert Richter <robert.richter@amd.com>

There is duplicate cleanup code in the init and exit functions. Now,
oprofile_arch_exit() is also used if oprofile_arch_init() fails.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch simplifies op_create_counter(). Removing if/else if paths
and return code variable by direct returning from function.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch removes some unnecessary goto statements.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Conflicts:
	arch/arm/oprofile/common.c
Signed-off-by: NRobert Richter <robert.richter@amd.com>

This patch fixes a resource leak on failure, where the
oprofilefs and some counters may not released properly.
Signed-off-by: NRobert Richter <robert.richter@amd.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: <stable@kernel.org> # .35.x
LKML-Reference: <20100929145225.GJ13563@erda.amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Now that we've got a generic perf-events based oprofile backend we might
as well make use of it seeing as SH doesn't do anything special with its
oprofile backend. Also introduce a new CONFIG_HW_PERF_EVENTS symbol so
that we can fallback to using the timer interrupt for oprofile if the
CPU doesn't support perf events.

Also, to avoid a section mismatch warning we need to annotate
oprofile_arch_exit() with an __exit marker.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Move the perf-events backend from arch/arm/oprofile into
drivers/oprofile so that the code can be shared between architectures.

This allows each architecture to maintain only a single copy of the PMU
accessor functions instead of one for both perf and OProfile. It also
becomes possible for other architectures to delete much of their
OProfile code in favour of the common code now available in
drivers/oprofile/oprofile_perf.c.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Tested-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

In preparation for moving the majority of this oprofile code into an
architecture-neutral place separate the architecture-independent code
into oprofile_perf_init() and oprofile_perf_exit().
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Tested-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

In preparation for moving the generic functions out of this file, give
the functions more general names (e.g. remove "arm" from the names).
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Tested-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Make op_name_from_perf_id() global so that we have a way for each
architecture to construct an oprofile name for op->cpu_type. We need to
remove the argument from the function prototype so that we can hide all
implementation details inside the function.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

Introduce perf_pmu_name() helper function that returns the name of the
pmu. This gives us a generic way to get the name of a pmu regardless of
how an architecture identifies it internally.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Signed-off-by: NRobert Richter <robert.richter@amd.com>

The number of counters for the registered pmu is needed in a few places
so provide a helper function that returns this number.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Tested-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NRobert Richter <robert.richter@amd.com>